Fluid mixing valve assembly

ABSTRACT

There is disclosed a mixing device for mixing a first fluid with a second fluid, the device including valve means for metering and controlling the amount of second fluid which is permitted to mix with the first fluid entering the device, the device generally including a mixing body having a fluid inlet for permitting entry of a first fluid, and a fluid outlet spaced therefrom, valve means interposed in the fluid path between the fluid inlet and fluid outlet for metering and controlling the amount of a second fluid entering the mixing body, the mixing body permitting the mixture of the first fluid with the second fluid, and the mixed fluids thereafter being permitted to exit from the mixing body through the fluid outlet. The valve assembly is manually operable and permits the operator to select the desired valve opening thereby to meter and control the amount of second fluid entering the mixing device.

United States Patent 11 1 Heath 1 1 Oct. 2, 1973 FLUID MIXING VALVEASSEMBLY Primary Examiner-Robert G. Nilson [75] Inventor: Walter Heath,Chicago, Ill. Atmmey Dommlk Knechtel & Godula [73] Assignee: ParklandInternational Inc., Melrose Park, Ill. [57] ABSTRACT [22] Filed: Dec. 6,1971 There is disclosed a mixing device for mixing a first fluid with asecond fluid, the device including valve Appl' 205204 means for meteringand controlling the amount of second fluid which is permitted to mixwith the first fluid [52] U.S. Cl 137/549, 137/604, 251/206 entering thedevice, the device generally including a [51] Int. Cl. Fl6k 19/00 mixingbody having a fluid inlet for permitting entry of [58] Field of Search137/549, 604; a first fluid, and a fluid outlet spaced therefrom, valve417/190; 251/206; 431/354, 355 means interposed in the fluid pathbetween the fluid inlet and fluid outlet for metering and controllingthe [56] References Cited amount of a second fluid entering the mixingbody, the UNITED STATES PATENTS mixing body permitting the mixture ofthe first fluid 1,253,143 1/1918 Caldwell 251/206 F e and fludshereafter 2953l60 9/1960 Brazier I 4 37/604 X bemg permltted to exitfrom the m1x1ng body through 2 74 0 5 195 Henningnu 37 549 X the fluidoutlet. The valve assembly is manually opera- 2,510,356 6/1950 w n251/20 x ble and permits the operator to select the desired valve1,679,219 7/1928 Huff .4 137/604 opening thereby to meter and controlthe amount of 3,024,806 3/l962 ColOnna 25l/206 X econd fluid enteringthe mixing device, 3,084,634 4/l963 McDougall 137/604 X 4 Claims, 10Drawing Figures PATENTEU 2 975 SHEET 1 [IF 2 FIG,

lllllll 1 FLUID MIXING VALVE ASSEMBLY BRIEF DESCRIPTION OF THE INVENTIONThe present invention is directed to a mixing device, for mixing a firstfluid with a second fluid which includes a valve assembly for meteringand controlling the amount of the second fluid which is permitted to mixwith the first fluid entering the mixing device. More specifically, themixing device of the present invention is particularly designed for thepurpose of facilitating and more accurately controlling the mixture ofoxygen with air, the oxygen-air mixture then being utilized inconnection with an oxygen tent, or other similar hospital appliance.

The apparatus of the present invention includes an adjustable valvemeans whereby an operator may select the desired ratio of oxygen to airby manipulating the valve means and hence, controlling the quantityorvolume of air which is permitted to enter the mixing device, and mixwith the oxygen entering the mixing device from a separate fluid inlet.Hence, the mixing device of the present invention achieves a greaterdegree of accuracy than heretofore obtainable by prior art type devices,represents a significantly more simplified construction manifestingitself in a lower cost, and is inherently easier to operate wherebypersons with only limited training may effectively operate the device.

BACKGROUND OF THE INVENTION The prior art with regard to valveassemblies is quite apparently a very crowded art field. undoubtedly,the only relevant manner of discussing prior art type valve assembliesis to view those assemblies whichhave particular applications in orderto adequately appreciate the field of use and the particular valveassembly as it affects that field of use. In this connection there areseveral prior art patents which illustrate valve means for mixingfluids, such as gases, in order to achieve a mixture which issubsequently delivered to a point for subsequent use.

Various prior art patents illustrate valve structures which appear to besomewhat similar, though not completely relevant to the structure of thepresent invention. For example, in U.S. Pat. No. 3,014,489, issued onDec. 26, 1961 to MC. Lamp Jr., et al., there is shown a gas valvestructure which includes a pair of discshaving a plurality of varioussized openings therethrough, the discs being rotated one with respect tothe other in order to control fluid flow and fluid mixture. In FIG. 1 ofthe drawings of the aforementioned patent, it is noted that the valveplate includes a plurality of apertures, each of which is larger thanthe next adjacent aperture. In addition, as shown in FIG. 2 of thedrawings therein, the valve assembly includes a plunger slideablymounted on a support which is secured to the body portion of the valveand is releasably urged by a spring into engagement with recesses,thereby to hold the valve plate in position with the desired sizeaperture in ,registry with the appropriate opening. However, it is to benoted that the valve assembly of the structure depicted in the -489patent includes many moving parts, and is therefore very intricate inconstruction and costly to manufacture. In this connection, it is notedthat this structure is designed to accommodate a pair of apertured discsfor controlling the fluid flow of two different fluids whereas the valveassembly of the present invention achieves a controlled mixture of twofluids by merely regulating and metering one fluid with respect to thesecond.

Another patent which illustrates a multiple oriflced valve is shown inU.S. Pat. No. 3,207,181, issued on Sept. 21, 1965 to R.S. Willis. Thevalve assembly illustrated therein includes a pair of rotatable discs,each disc having a pair of openings. Each of the two discs is rotatablymovable, one with respect to the other, and by rotating either or bothof the discs, the mixture of the gas entering through the gas valve andhence, through the openings in the appropriate discs, is therebyregulated and controlled. It is to be noted that the valve assembly asshown in the 181 patent hence of necessity, must have a pair of discseach having a pair of openings which are rotatably moved one withrespect to the other, thereby to vary the horizontal alignment of theapertures, thereby to control the aperture size andhence, fluid flowtherethrough. The present invention, on the other hand, contemplates amore accurate and precise means of controlling fluid flow by having aparticular aperture selected to achieve a particular concentration ofone fluid with respect to the other. In this manner, a more precise andcontrolled fluid mixture is obtained. Furthermore, the valve assembly asshown in the 181 patent, once again, includes many moving parts and istherefore not only difficult to construct, but quite costly inmanufacture.

.In U.S. Pat. No. 2,534,046, issued on Dec. 12, 1950, to G.A. Mau, thereis shown another form of valve constructionutilized in connection withproportioning devices. This type of valve structure has an aperturevalve plate, which once again, controls the fluid flow by means ofmoving this plate into and out of horizontal alignment with the fluidflow line. It will be noted, however, that once again, a more imprecisefluid mixture would be obtained since it is inherently more difficult tocontrol the size of the aperture controlling the volume or quantity offluid passing through, since the operator is relying upon the relativedegree of opening achieved by moving the pivotal plate with respect to afixed plate in order to adjust the size of the opening. The presentinvention, as has been indicated hereinabove, achieves a high degree ofaccuracy since a specific aperture size is utilized in order to achievea particular concentration ofthe fluid entering therethrough and whichis subsequently mixed with the second fluid. In this manner, a veryhighly controlled mixture of two fluids is achieved.

Another valve structure which teaches the use of an apertured disc isshown in U.S. Pat. No. 2,889,852, issued on June 9, 1959 to J.L. Dunlap.As particularly noted in FIG. 3 of the drawings, there are two inletlines and two exit lines for fluid to flow through, the apertures in thevalve disc being in horizontal alignment with the aforementioned inletand exit lines. Fluid flow is controlled by means of turning the valvedisc plate such that the two apertures disposed therethrough are takenout of perfect horizontal alignment with respect to the inlet lines,thereby decreasing the size of the aperture through which fluid ispermitted to flow. It is clear that in order to permit the valveassembly of the -852 patent to be operable, it is necesary that thevalve plate be disposed between a pair of plates which are alsoapertured such that by movement of the centrally disposed valve plate ordisc, the apertures disposed therein cooperate with the apertures in thetop and bottom plates thereby to increase or decrease respectively theaperture size. Once again, while a valve structure has been obtainedwhich controls fluid flow therethrough, nevertheless, precise controland regulation of the amount of fluid through the valve disc aperturesis difficult, since one is relying upon the relative degree of openingpermitted by opening of the disc plate with respect to the top andbottom plates respectively. Hence, it is apparent that the same problemnoted with respect to the other prior art type valve structuressimilarly appear in the aforementioned device.

A multitude of other prior art patents and prior art devices exist withrespect to valve structures. Usually, such valve structures and devicesare designed to accomplish specific functions and purposes and hence, inthe usual case, it is virtually impossible to apply a particular knownvalve structure to a different or varied intended purpose or function.For example, none of the prior art valve structures discussedhereinabove are concerned particularly with the problem of achieving aprecise and controlled mixture of air and oxygen such as is used inconnection with oxygen tents, oxygen hoods, oxygen masks, or otherequipment utilized to provide an artifical oxygen-air environment for apatient.

It is therefore the principal object of the present invention to providea valve assembly which is relatively simple in construction, but whichnevertheless, operates to provide a controlled and precisely regulatedmixture of oxygen and air especially useful in connection with patienttreatment.

Another object of the present invention is to provide a valve assemblywhich is relatively simple in construc tion and includes a mixing bodyhaving a fluid inlet and a fluid outlet, an aperture disposed in saidmixing body intermediate the fluid inlet and fluid outlet, a valveassembly, including means for removable engagement in the aperture, thevalve assembly including a top closure plate, a bottom closure plate,and valve means fixedly secure between the top plate and the bottomplate, the valve means being adjustable so as to regulate the volume offluid passing therethrough, whereby controlled mixture of two fluids maybe obtained when a first fluid is permitted to enter through the fluidinlet of the mixing body and the second fluid is permitted to enterthrough the valve means, the second fluid being controlled and regulatedin terms of concentration with respect to the first fluid.

In connection with the foregoing object, it is another object of thepresent invention to provide a valve assembly of the type set forth,wherein the valve means comprises an apertured valve disc including aplurality of circumferentially disposed apertures disposed therethrough,each of the apertures having a slightly greater diameter than the nextadjacent aperture whereby the rotational movement of the valve meanswill cause the registry of one of the apertures with an inlet opening ina the valve means thereby to permit a controlled amount of fluidtherthrough for mixture with another mixture entering through the fluidinlet of the mixing body producing a controlled mixture of the twofluids.

Yet a further object of the present invention is to provide a mixingbody and valve means assembly which further includes a filter meansassociated with the valve assembly thereby to filter the fluid enteringinto the valve assembly from the atmosphere to produce a dustfreemixture of two fluids.

Another object of the present invention is to provide a mixing body andvalve assembly of the type described, which is so constructed as toprovide a venturi effect in order to achieve a uniform and thoroughlymixed concentrations of gases or fluids as the same pass through themixing body.

Yet a further object of the present invention is to provide a mixingbody and valve assembly wherein the valve assembly has a simplifiedconstruction including a top plate, a bottom plate, and a valve discplate interposed therebetween, the valve disc plate held in biasedrelationship with respect to the top plate by means of spring biasingmeans, and which further includes intermittent stop means forfacilitating the accurate registry of one of the apertures in the valvedisc in registry with the appropriate inlet opening in the valveassembly to permit fluid to enter the mixing body and mix with the fluidentering through the fluid inlet disposed in the mixing body.

In connection with the foregoing object, it is another object of thepresent invention to provide handle means external of the valveassembly, the handle means being connected to the valve disc whereby theoperator may cause rotation of the valve disc by rotatably moving thehandle means thereby to effect registry of the appropriate or desiredaperture in the valve disc with the inlet opening disposed in the valveassembly.

Further features of the invention pertain to the particular arrangementof the elements and parts whereby the above-outlined and additionaloperating features thereof are attained.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof will best beunderstood by reference to the following specification, taken inconnection with the accompanying drawings in which:

FIG. 1 is a top plan view of the mixing body and valve assembly of thepresent invention showing the valve assembly in positon in relation tothe mixing body;

FIG. 2 is a side elevational view, partly in cross section, showing theengaged relationship between the valve assembly and the mixing body;

FIG. 3 is a side cross sectional view showing the valve assembly and themixing body in juxtaposed relationship taken in the direction of thearrows along the line 33 of FIG. 1;

FIG. 4 is a side cross-sectional view of the nozzle forming the fluidinlet of the mixing vent and showing the venturi tube which produces theventuri effect;

FIG. 5 is a top plan view of the top plate of the valve assembly;

FIG. 6 is a side cross-sectional view of the top plate of the valveassembly taken in the direction of the arrows along the line 66 of FIG.5;

FIG. 7 is a top plan view showing the valve disc plate including aseries of circumferentially disposed apertures therein which forms apart of the valve assembly;

FIG. 8 is a side cross-sectional view of the valve disc plate taken inthe direction of the arrows along the line 8-8 of FIG. 7;

FIG. 9 is a top plan view of the bottom plate forming a part of thevalve assembly; and

FIG. 10 is a side cross-sectional view of the bottom plate forming apart of the valve assembly taken in the direction of the arrows alongthe line 10-10 of FIG. 9.

Referring now more particularly to FIGS. 1 and 2 of the drawings, themixing body and valve assembly of thc presentinvention is moreparticularly illustrated. The complete valve apparatus, generallyreferred to by the numeral l2'herein, generally comprises a mixing body14, a nozzle element 16, and a valve assembly 18. As shown in FIG. 1,the upper portion of the valve assembly 18 includes a plurality ofnumerical indicia, which are provided for a purpose to be describedhereinafter, and a rotatable handle member 20, which may be manuallyrotated and set at one numerical indicia.

FIG. 2 more clearly indicates the positional relationship of the valveassembly 18 with respect to the mixing body 14. It will be noted that inthe preferred embodiment, the valve assembly 18 is generally circular inconfiguration, and includes a filter support screen 22 circumferentiallydisposed about the valve assembly 18 which carries and supports a filter23 for filtering larger particular matter from the second fluid. Thevalve assembly 18 is shown to be press-fitted into an appropriateaperture disposed in the mixing body 14 in a manner which will be morefully described hereinafter.

As more particularly shown in FIG. 3 of the drawings, the mixing body 14of the valve apparatus 12, is provided with a threaded fluid inletaperture 24 which accommodates therein the nozzle element 16. For thesake of convenience, the portion of the mixing body 14, having thethreaded inlet aPerture 24 therein shall be referred to as the forwardend of the mixing body 14, and the opposed end of the mixing body 14shall be referred to as the rearward portion thereof. Immediatelyrearward of the threaded inlet aperture 24 is a mixing chamber 26 whichis generally circular in configuration and is open to the atmosphere atone end thereof, and having a closed lower end. The upper end 28 of themixing chamber 26 forms an aperture which accommodates therein the valveassembly 18 in press-fitted engagement, in a manner to be more fullydescribed hereinafter.

Rearward of the mixing chamber 26, is a frustoconical section 30, whichin turn, terminates at its rearward end in a delivery tube receivingchamber 22. The receiving chamber 32 has an inner diameter the same asor slightly greater than the diameter of a delivery tube 34, which isinserted therein, either in press-fitted relationship or in some othersuitable manner.

Hence, it will be observed that a fluid such as gas or the like, whichis delivered into the mixing body 14, through the nozzle element 16,when threadedly engaged in the threaded inlet aperture 24, air ispermitted to pass through the mixing body via mixing chamber 26, firstconical section 30 and delivery tube receiving chamber 32, and henceinto the delivery tube 34 for ultimate delivery to either the patient orsome other medical equipment such as a nebulizer or the like.

FIGS. 3 and 4 illustrate the construction of the nozzle element 16, andas shown more particularly in FIG. 4, the nozzle element is of unitaryconstruction and includes a series of diametrically increasing tuberetention rings 36 at one end thereof, which rings 36 are designed toreceive, grasp and hold an appropriate delivery tube (not shown) in themanner known in the art, and the opposed end of the nozzle element 16 isshown to be threaded as at 38, the threads 38 being so constructed as tothreadedly mate with the threaded inlet aperture 24. It will further benoted that the nozzle element [6 includes a central core 40 which is ofsubstantial uniform diameter throughout the length of the nozzle elementfrom the outer inlet end 41 to a point 42 set slightly rearwardly fromthe inner end 43, the point 42 representing the point of taper of thecentral core 40. The core 40 tapers commencing at point 42 therebyforming a conical section 44 and terminating in a diametrically reducedshort core section 45 through which the gas fluid is delivered into themixing body 14. Finally, the nozzle element 16 is providedwith acircumferentially flanged lip 46, which seats against the outer surfaceof the mixing body 14 when the nozzle element 16 is threadedly engagedin the threaded inlet aperture 24 of the mixing body 14, as more clearlyshown in FIG. 3.

The construction of the valve assembly 18 will be better understood byreference to FIGS. 5 through 10 of the drawings, wherein the variouscomponents of the valve assembly 18 are illustrated.

With reference to FIGS. 5 and 6 of the drawings, there is shown a topplate 50, forming the top portion of the valve assembly 18. The topsurface 51 is provided with a central well 52, in which a plate or otherdecal having appropriate numerical indicia is disposed in the mannershown in FIG. 1, the well 52 further accommodating therein thedisposition of the handle member 20. The top plate further includes acentral tubular core 54 which accommodates therethrough the shaft of thehandle member 20 in a manner to be described hereinafter. The top plate50 is further provided with a series of circumferentially disposedstandoffs 56, the stands-offs 56 being spaced slightly inwardly from theouter periphery of the top plate 50. Each of the stand-offs 56 includesa centrally disposed threaded bore 58 which extends for a distance alongthe length of the stand-off 56. The undersurface 59 of the top plate 50is provided with an undercut circumferential groove 60 for a purpose tobe described more fully hereinafter.

The tubular core 54 is shown to be surrounded by a circular spring guide55, the function and purpose of the spring guide 55 being more fullyappreciated with reference to FIG. 3 and the discussion followinghereinafter.

Finally, a tubular spring well 62 is formed on the undersurface 59 ofthe top plate 50, which, again, functions for a purpose to be more fullydescribed hereinafter.

In FIGS. 9 and 10 of the drawings, the bottom plate 65, which comprisesa part of the valve assembly 18, is illustrated.

In the embodiment shown in the drawings and described hereinafter, thebottom plate 65 is shown to be a separate element forming a part of thevalve assembly 18. However, it is contemplated that in the commercialembodiment of this apparatus, the mixing body 14 and bottom plate 65will be formed as a one-piece construction. That is, it is considered tobe more economical in cost and more simplified in construction to formthe bottom plate 65 as a unitary part of the valve assembly 18. In sucha contemplated embodiment, the only separate key elements of the valveassembly 18 would be the top plate 50 and the valve plate disc 80. Sincethe bottom plate 65 is immovable with respect to the mixing body 14 inoperation, the functioning of the apparatus is unaffected while at thesame time, the anticipated cost of manufacture and time of assembly isreduced. Hence, it will be apparent that whether the bottom plate 65 isformed integrally with the mixing body 14, or as a separate element ismerely a matter of manufacturing techniques and does not affect theoperation of the valve apparatus 12. The bottom plate 65 is shown to bein the form of a circular disc having substantially the same diameterasthe circular configuration of the top plate 50. The bottom plate 65 isshown to be provided with a series of circumferentially arrangedapertures 66 disposed therethrough, each of the apertures 66 being sopositioned as to be in vertical alignment with a corresponding threadedbore 58, in a corresponding stand-off 56 when the top plate 50 andbottom plate 65 are positioned in mating engagement. The top plate 50and bottom plate 65 are held in mating engagement by means of a pluraltyof screws 68 (FIG. 3) which are disposed through a correspondingaperture 66 in the bottom plate 65 and threadedly engaged in acorresponding threaded bore 58 of a stand-off 56, the stand-off S6positioning the top plate 50 and bottom plate 65 in spaced relationshipwith respect to one another. The bottom plate 65 further includes acentral well 69 which accommodates the lower end of a shaft 100interconnecting the handle element with the valve plate disc 80. Thebottom plate 65 is similarly provided with an undercut circumferentialgroove 70 which cooperates with the circumferential groove 60 in the topplate 50, for retaining the filter support screen 22 therebetween, inthe manner shown in FIG. 2 of the drawings.

The bottom plate 65 is further provided with a gas inlet opening 72disposed therethrough at a point substantially intermediate the centralwall 69 and the outer periphery of the bottom plate 65. The undersurface 67 of the bottom plate 65 is provided with a circumferentialcollar 74, extending downwardly from the under surface 67 thereof andsurrounding the lower end of the gas inlet opening 72 whereby gas flowis permitted through the inlet opening 72 and through collar 74. Theouter diameter of the collar 74 is the same as, or slightly smaller thanthe diameter of the upper end 28 of the mixing chamber 26 wherebyfluid-tight pressfitted seatment is established when the collar 74 ispressed into and seated in the upper end 28 of the mixing chamber 26.

The valve assembly 18 is completed by means of the valve plate disc 80,which is illustrated in FIG. 7 and 8 of the drawings. The valve platedisc 80 is shown to include a circumferentially arranged series ofapertures 82, each of the apertures being slightly greater in diameterthan the next adjacent aperture. The valve plate 80 is similarlycircular in configuration but has an overall diameter which is slightlyless than the diameter of the circle formed by the inner surfaces of thestand-offs 56 whereby the valve disc plate 80 is conveniently positionedand retained inside of the circle formed by the stand-offs 56 andpositionally held between the top plate 50 and the bottom plate 65. Theunder surface 83 of the disc plate 80 is provided with an upstanding lug84 which is centrally cored as at 86, the central core 86 extendingthrough the lug 84 and completely through the body of the valve discplate 80. The central bore 86 accommodates the placement therethrough ofthe shaft 100. It will be noted that the lug 84 is also provided with across bore 88 which is in registry with a similar cross bore 102provided to the shaft 100. The shaft 100 is held in fixed relationshipwith respect to the valve disc plate 80 by means ofa pin 104 which isfrictionally inserted through cross bore 88 and cross bore 102, wherebythe rotational movement of the handle element 20 will cause thecorresponding rotational movement of the valve disc plate 80. Theapertures 82 in the valve disc plate 80 are so positioned that each ofthe apertures 82 will be in vertical alignment with the gas inletopening 72 in the bottom plate and with the opening formed by thecircumferential collar 74. Finally, the valve disc plate is shown to beprovided with a series of detent stops also arranged in circumferentialarrangement and positioned intermediate the apertures 82 and the centralcore 86. It will be noted that a detent stop 90 is provided intermediatethe central core 86 and each of the apertures 82, thereby to create astop position with respect to each of the apertures 82.

With reference to FIG. 3, the complete assembly of the valve apparatus12 of the present invention is illustrated. As has been indicatedhereinabove, the top plate 50 is held in spaced fixed arrangement withrespect to the bottom plate 65 by means of screws 68 which are insertedthrough the apertures 66 in the bottom plate 65 and into the threadedbores 58 positioned in each of the stand-offs 56. The valve disc plate80 is held in spaced relationship with respect to the top plate 50 bymeans of a spring 92 which is positioned about spring guide 55 of thetop plate 50 and the lug 84 of the bottom plate 65. The spring 92 tendsto keep the valve disc plate 80 in spaced away and spring biasedrelationship with respect to the top plate 50, holding the same in fixedsecure relationship. It will further be noted that the tubular springweld 62 formed in the undersurface 59 of the top plate 50 is providedwith a stop spring 94 and having a ball bearing 95 disposed at the lowerend thereof. The stop spring 94 tneds to urge the ball bearing 95downwardly and against the valve disc plate 80, the ball bearing 95cooperating with the detent stop 90 in the valve disc plate 80 therebyto provide intermittent stops adjacent each of the apertures 82positioned circumferentially in the valve disc plate 80. Hence, in orderto select an appropriately sized aperture 82, as desired by theoperator, the operator need only rotate handle element 20, which isconnected to the valve disc plate 80 by means of the shaft in the mannerdescribed hereinabove, until the appropriate aperture is located, asindicated by the numerical indicia as shown in FIG. 1, such rotation ofthe handle element 20 causing a corresponding rotational movement of thevalve disc plate 80. The ball bearing 95 will roll over the de tentstops 90 and will ultimately rest in the particular detent stop 90 whichis adjacent the corresponding aperture 82 selected by the operator. Thespring 92 retains the valve disc plate 80 in biased relationship withrespect to the top plate 50. It will further be noted that a smallshoulder 97 is provided in opposed spaced relationship with respect tothe gas inlet opening 72, and further, a peripherally raised collar 98surrounds the gas inlet opening 72, the height of the peripheral collar98 and shoulders 97 being substantially the same whereby the valve discplate is kept in slightly spaced relationship with respect to the bottomplate 65. It will be appreciated therefore, that the valve disc plate 80is maintained in position by means of the spring 92 and the shoulder 97and peripheral collar 98.

It will further be noted that the circumferential grooves 60 and 70respectively cooperate to retain the filter support screen 22therebetween, the filter 23 carried by the filter screen 22 extending360 peripherally around the valve assembly 18. The complete valveassembly, once assembled achieves a fluid tight seal, whereby any andall air entering through the filter 23 is filtered prior to its deliverythrough the pre-selected aperture 82, gas inlet opening 72 and theopening defined by the collar 74 into the mixing body 14 for mixturewith oxygen being introduced into the mixing body through the centralcore 40 of the nozzle element 16. The pre-selection of an appropriateaperture 82 thereby regulates the quantity or volume of air which ispermitted to enter into the mixing body 14 and which is furtherpermitted to mix with regulated volume of oxygen entering into themixing chamber 26 of the mixing body 14.

As was indicated hereinabove, the central core 40 is tapered thereby toform a conical section '44 terminating in a reduced core section 45,thereby creating a venturi effect. As oxygen is introduced intothe core40 and is forced through the conical section 44 into the reduced coresection 45, the velocity of gas flow is thereby increased which, inturn, causes a vacuum effect at the lower end of the mixing chamber 26,thus drawing air into the chamber 26 for mixture with the oxygentravelling therethrough. This construction assures a good mixture ofoxygen with air as the same is introduced into the mixing chamber 26 andfor subsequent delivery through the delivery tube. Once the desiredquantity of air and oxygen has been mixed in the mixing chamber, themixture is directed through the frusto conical section 30 of the mixingbody 14, and into the delivery tube 34. Hence, due to the constructionof the mixer body 14 and nozzle element 16, the flow of the first fluidis accelerated thereby creating a subatmospheric lateral pressure in themixing chamber 26 intraining the second fluid which then mixes with thefirst fluid. By varying both the size of the jet and the size of theaperture 82 in the valve plate disc 80, a precise mixture of the twofluids can be attained.

As has been indicated hereinabove, the complete valve assembly 18 isconnected to the mixing body 14 by press fitting the circumferentialcollar 74 into the upper end 28 of the mixing chamber 26. The dimensionsof the collar 74 and mixing-chamber 26 are such that a fluid tight pressfitted relationship is achieved. It will further be appreciated that dueto this construction, the device may be easily disassembled to eitherrepair any defective part, or to clean the interior portion of the valveassembly 18. Of course, such disassembling is further facilitated wherethe bottom plate 65 is formed integrally with the mixing body 14 sincefewer parts or elements are involved in the disassembling procedure.Again, it will be appreciated that no significant change of functionresults from such an alternate construction.

The mixing body 14, nozzle element 16, top plate 50 and valve disc plate80 are all preferably formed of anodized aluminum which is lightweightand easily machinable. The bottom plate 65 is preferably formed of aplasticized material since it is desirable to have the collar 74 formedof a plastic material thereby to achieve a good press fittingrelationship between the collar 74 and the upper end 28 of the mixingchamber 26.

Where the bottom plate 65 is formed integrally with the mixing body 14,such a unitary element would be formed of anodized aluminum since theneed for a press-fit between the collar 74 and the upper end 28 of themixing chamber 26 is obviated.

With regard to the filter 23, in the preferred embodiment, the filter 23is formed of an elasticized material whereby the filter 23 may be easilymounted about the valve assembly 18. Furthermore, replacement of thefilter 23 is thereby facilitated since the operator need not disassemblethe apparatus 12in order to change the filter 23 but merely stretchesthe spent filter to remove the same and replace with a new filter. Ifdesired, the filter 23 may be formed of a material having bacterialfiltering properties so as to function as not only a filter forparticular. matter, but also as a bacterial filter. Hence, the selectionof a filter material is deemed to be dependent upon the intended use ofthe apparatus 12.

It will therefore be appreciated that there has been provided by virtueof the present invention, a relatively simplified construction of avalve assembly and mixing body device which is particularly designed forachieving a controlled and precise mixture of oxygen and air which isparticularly useful in connection with medical treatment procedureswhere a controlled environment is desirable or necessary. The valveapparatus of the present invention permits ease of assembly anddisassembly whereby the various parts thereof may be repaired,exchanged, or changed where necessary, without at the same timerequiring a high degree of mechanical skill. Furthermore, the valveapparatus of the present invention will result in the achievement of avery controlled and precise oxygen and air mi ture while at the sametime avoiding the necessity of having a highly trained operator requiredin order to successfully operate the apparatus.

It will therefore be appreciated that all of the above objects andadvantages have been accomplished by means of the valve apparatusdepicted herein and various embodiments thereof to provide an extremelycompact and low cost, while at the same time, highly precise valvestructure.

While there has been described what at present is considered to be thepreferred embodiment of the present invention it will be understood thatvarious modifications will be made herein and it is intended to cover inthe appended claims all such modifications as fall within the truespirit and scope of the invention.

What is claimed is:

1. An apparatus for metering and mixing a first fluid with a secondfluid comprising, in combination,

a mixing body having a fluid inlet and a fluid outlet,

an aperture disposed in said mixing body intermediate said fluid inletand said fluid outlet,

a valve assembly removably engaged in said aperture,

said valve assembly comprising,

a top closure plate,

a bottom closure plate, said bottom closure plate being spaced from saidtop closure plate,

said top plate including a plurality of stand-offs extending downwardlyfrom one surface thereof and, in use, contacting said bottom plate,thereby to maintain said top plate and said bottom plate in spacedrelationship,

valve means fixedly disposed between said top and bottom closure plates,said valve means being adjustable so as to regulate the volume of asecond fluid entering said mixing body through said valve means,

whereby the first fluid entering said inlet of said mixing body ispermitted to mix with a metered amount of the second fluid enteringthrough said valve means so as to produce a controlled mixture of thefirst and second fluids.

2. The metering and mixing apparatus as set forth in claim 1 above,wherein said valve means is disposed in juxtaposed relation and adjacentto said bottom plate, and said valve means being rotatably movable withrespect to said top plate and bottom plate.

3. The metering and mixing apparatus as set forth in claim 2 above,wherein said bottom plate includes a collar extending downwardly fromone surface thereof, said collar defining an aperture extending throughsaid bottom plate and said collar, and said valve means includes aplurality of various sized openings disposed therethrough incircumferential relation, said openings in said valve means being sodisposed such that on rotation of said valve openings, one of saidopenings in said valve means may be caused to register with saidaperture in said bottom plate thereby to control the volume of secondfluid entering therethrough into said mixing body.

4. The metering and mixing apparatus as set forth in claim 3 above,which further includes handle means fixedly secured to said valve meansand extending through said top plate thereby to provide external meansfor rotatably moving said valve means thereby to cause the registry ofone of said various sized openings in said valve means with saidaperture in said top plate to provide a fluid path for the first fluidinto the mixing device.

1. An apparatus for metering and mixing a first fluid with a secondfluid comprising, in combination, a mixing body having a fluid inlet anda fluid outlet, an aperture disposed in said mixing body intermediatesaid fluid inlet and said fluid outlet, a valve assembly removablyengaged in said aperture, said valve assembly comprising, a top closureplate, a bottom closure plate, said bottom closure plate being spacedfrom said top closure plate, said top plate including a plurality ofstand-offs extending downwardly from one surface thereof and, in use,contacting said bottom plate, thereby to maintain saId top plate andsaid bottom plate in spaced relationship, valve means fixedly disposedbetween said top and bottom closure plates, said valve means beingadjustable so as to regulate the volume of a second fluid entering saidmixing body through said valve means, whereby the first fluid enteringsaid inlet of said mixing body is permitted to mix with a metered amountof the second fluid entering through said valve means so as to produce acontrolled mixture of the first and second fluids.
 2. The metering andmixing apparatus as set forth in claim 1 above, wherein said valve meansis disposed in juxtaposed relation and adjacent to said bottom plate,and said valve means being rotatably movable with respect to said topplate and bottom plate.
 3. The metering and mixing apparatus as setforth in claim 2 above, wherein said bottom plate includes a collarextending downwardly from one surface thereof, said collar defining anaperture extending through said bottom plate and said collar, and saidvalve means includes a plurality of various sized openings disposedtherethrough in circumferential relation, said openings in said valvemeans being so disposed such that on rotation of said valve openings,one of said openings in said valve means may be caused to register withsaid aperture in said bottom plate thereby to control the volume ofsecond fluid entering therethrough into said mixing body.
 4. Themetering and mixing apparatus as set forth in claim 3 above, whichfurther includes handle means fixedly secured to said valve means andextending through said top plate thereby to provide external means forrotatably moving said valve means thereby to cause the registry of oneof said various sized openings in said valve means with said aperture insaid top plate to provide a fluid path for the first fluid into themixing device.